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Is there any section of SRAM data retained through a watchdog reset?

Robert Paradiso
Intellectual 420 points
Other Parts Discussed in Thread: CC3200

I see in the documentation "Internal RAM is capable of selective retention during LPDS mode." Can this or similar be used to have some data survive a watchdog reset? I have some state that I need to have survive even in this case, but constantly writing it to Flash is not an option since it would wear out the Flash memory.

Thanks,

-Bob

  • 0
    Genius 3690 points

    NOTE: In CC3200 R1 device, it is highly recommended that the application software, when
    rebooting after a WDT reset, requests the PRCM for Hibernation (see Section 15.3.10) for
    10mS of and resume its full functionality only after returning from this hibernation. This is
    effective for full recovery from any complex stuck-at scenario that involves the WiFi
    subsystem.

    It is mentioned in TRM that whenever watch dog reboots you must go into a hibernate cycle for a complete recover .. In Hibernate ram retention is not possible .. So In watchdog reset it is not possible ................

  • 0
    TI__Genius 16370 points
    Robert,

    The whole of SRAM is by default retained across a WDT reset, but please note the below points:
    - The bootloader loads the application binary to SRAM for execution after a WDT reset. Meaning, the code section is overwritten - You should allocate some memory in non-code region which doesn’t get initialized across a WDT reset.
    - After a WDT reset, the device must execute a hibernate cycle, and this process will clear the SRAM (Please refer 'Note' of Section 10.2 of CC3200's TRM for more details). Meaning, the backed up (state) information shall be pushed to non-volatile memory.

    -/Praneet
  • 0 in reply to Praneet Kumar
    TI__Genius 16370 points
    Robert, I'm closing this thread - For any followup queries, request you to start a new thread w/ references to the current one for us to track it better.

    -/Praneet